Nordic Pure 20x25x4 (3-5/8 Actual Depth) MERV 13 Plus Carbon AC Furnace Air Filter, Box of 1 Actual Size of Carbon Air Filter: 19 1/2 x 24 1/2 x 3 5/8 Activated charcoal flat panel added to increase odor control Removes tobacco and fireplace smoke, along with all contaminants removed by a MERV 12 filter Ideal for customers looking for superior filtration but needing an odor control element Made in the USA